JP-A-11-160464 conventionally discloses a solar energy operating type wireless control timepiece and JP-A-2001-166071 discloses a self electricity generating type electronic timepiece. Each timepiece receives the standard radio wave including the time information of high accuracy such as a year, a month, a day, an hour, a minute, a correct second, summer time information, etc. transmitted every one minute as a technique for receiving time data from the exterior and correcting the time displayed at present, and automatically makes a time correction as time setting, a date correction, etc.
In Japan, the standard radio wave is transmitted at present from a transmission station located in Fukushima prefecture at a frequency of 40 KHz. However, in an area such as a Kyushu district, etc. separated by 1000 Km or more from the transmission station of the Fukushima prefecture, the intensity of an electric field is weak and there are areas unable to sufficiently receive the standard radio wave. Therefore, a new transmission station is being constructed in Saga prefecture of Japan in the year of 2001. The frequency of the standard radio wave transmitted from this transmission station of the Saga prefecture is 60 KHz, and it is necessary to switch the receiving frequency and the receiving algorithm to a receiving frequency and a receiving algorithm corresponding to this area so as to set the signal receiving range of the radio correcting timepiece to the whole country of Japan. Further, the frequency of the standard radio wave and a time code format, etc. are different in accordance with respective countries and areas. Therefore, it is necessary to switch the receiving frequency and the receiving algorithm to the receiving frequency and the receiving algorithm according to the area so as to cope with the standard radio waves.
On the other hand, JP-B-56-17629 discloses a timepiece having a correcting means using the radio wave in which the pattern of a time signal mixed with a voice signal and broadcasted from a broadcast station, etc. is stored in advance and broadcast waves from plural broadcast stations are sequentially received in a constant period, and the time correction is made by recognizing the time signal waveform. Namely, when the intensity of the electric field of the radio station is too weak to receive the signal, the signals of other broadcast stations are sequentially received in a predetermined pattern, and the signal reception of each broadcast station is repeated until the signal can be received.
However, although JP-A-11-160464 discloses the solar energy operating type wireless control timepiece and JP-A-2001-166071 discloses the self electricity generating type electronic timepiece as mentioned above, these inventions do not disclose the case that required radio wave can not be received by the difference in radio wave intensity according to the area. In the above disclosure of JP-B-56-17629, its main object is not to receive the standard radio wave including the time information of high accuracy, but is to receive one time service signal in one hour. In such a signal receiving system, where electricity saving is required as in a compact portable timepiece, it is necessary to set signal receiving periods during short times before and after a correct time. Therefore, when a large time error is caused, the case that it is difficult to automatically correct the time is caused. Further, in the construction for receiving the time signal, the next time signal is received after at least one hour has passed. Therefore, a period required for the correction is lengthened.
Therefore, an object of this invention is to provide a radio correcting timepiece which reduces the influence of a radio wave situation of the standard radio wave according to an area, and can cope with the case causing a large time error, and can make a correction to the exact time in a shorter period.